Paper manufacture



Patented Oct. .16, 1934 UNITED STATES- PATENT OFFICE PAPER MANUFACTUREHarold Robert Barton, Andover, Mass assignor to Rafl'old ProcessCorporation, a corporation of Massachusetts No Drawing ApplicationNovember 29, 1932, Serial No. 644,999

2s maime- (01. 92-21) no deteriorated sizing.

A further object is to improve the sizing of paper filled with alkalinefiller made from a fibrous mix containing sizing, or undeveloped sizing.

A further object is to manufacture paper of imis proved sizing qualityand filled with alkaline filler from a fibrous mix containing alkalinefiller, which alkaline filler hasa tendency in certain cases todeteriorate or destroy the sizing on the driers of a paper machine.

Other objects and advantages of my invention will become apparent duringthe course of the following description.

' In my copending application Serial No. 501,674, filed December 11,1930,'now Patent No. 1,922,325, granted August 15, 1933, I disclose amethod of manufacturing sized paper filled with alkaline filler by theapplication of size and size precipitant to a paper web containingalkaline filler. Alternatively, the precipitant may be applied to thepaper mix and the size to the web, or the size to the paper mix and theprecipitant to the web, or precipitated sizing may be applied to theweb. The claims ,in that application cover the practices disclosed,certain of the claims reading broadly to the application to the paperweb of a size precipitant such as acidic material, for example alum; ina, process wherein a sizing agent is employed and wherein there isproduced by the action of the precipitant applied to the web asubstantially water insoluble substance capable of imparting sizingefiect to said web. It is also disclosed in said'application that theprocedure employed therein may be used to impart additional sizing to aweb containing alkaline filler already sized by other methods, such forexample, as those methods disclosed in my then ccpending applicationsSerial Nos. 304,168 and 304,172, both filed September 5, 1928, and nowtured into Patents Nos. 1,803,643 and 1,803,647, both issued May 5,1931. Briefly, these two patents disclose respectively a method ofemploying size suchas rosin size to size paper containing ae filler, in"which method the fibrous mix containing rosin size which has beenprecipitated as with alum in the beater is treated with a sizingrestoring agent just prior to formation of thepaper web; and a methodemploying size such as rosin size to size paper filled with alkalinefiller, wherein the fibrous mix is treated with a size precipitant justprior to formation of the paper web.

The procedures shown in the above patents entail the addition either ofa restoring agent or precipitant under conditions favoring the mini- Imizing of the time and/or intimacy of contact of the constituents of themix, and thereby overcome or avoid the deterioration ordinarily takingplace when sizing such as a size precipitate, for example, a rosin sizeprecipitate, comes in contact with alkaline filler such as in thebeater.

I have now devised a process which is in some of its aspects amodification of the general process covered broadly by certain of theclaims of my copending application first above mentioned.

This process may be described briefiy as that of producing, restoring,preserving and/or improving sizing in a paper web containing alkalinefiller by the application of a suitable sizing aifecting agent to theweb, said web already containing either destroyed sizing, deterioratedsizing, undeveloped or underdeveloped sizing, or substantiallyundeteriorated sizing. This is accomplished without the application ofadditional sizing agent to the web, the sizing aifectinguagent appliedto the web not being a sizing agent, but rather one which may act inconjunction with or upon a sizing agent or sizing.

However, in my invention the sizing afiecting agent does not act with orupon a soluble or emulsified sizing agent precipitable but theretoforeunprecipitated, but rather with or upon a sizing agent or sizing whichis either unprecipitable or which is added in precipitated form or whichhas already been precipitated, or which having been once precipitated orflocculated is now in a form such as either does not impart any sizingat all or not complete sizing, or would sufier deterioration in theabsence of said sizing aiiecting agent, "in either of these alternativesthe sizing agent or sizing being already in the mix prior to webformation.

In many of theOsizing. procedures used'with papers filled with alkalinefiller, it has been ob served that somewhat more sizing agent may berequired than in papers filled with non-alkaline filler. I believe thatthis, in certain cases, may be due to the fact that the sizing, althoughsatisfactory when the min is delivered to the webiorming device, issomewhat deteriorated in the wet web by contact with the alkalinefiller. This Hill deterioration probably takes place only to'a limitedextent, if at all, at room temperature, (i. -e. in the web at any timebefore the driers are reached), but it is probably substantiallyaccelerated on the driers by the temperatures employed in drying. Theapplication of the present invention substantially prevents suchdeterioration of the sizing by the alkaline filler and thus permitssubstantially the full development of the sizing. This, as will beapparent, results in certain cases in considerable economy in sizingagent.

Several illustrative instances in which my invention may be practicedare given below, but of course it will be understood that theseinstances are not to be taken as limiting, because as will be apparentto one skilled in the art, my invention is capable of broad application.

(1) A mix made with fibrous material, alkaline filler, size such asrosin size, and alum in the concentrated stage of the papermakingprocess, such as in the beater, will normally have its sizing efiectgreatly deteriorated if not completely de stroyed by the time the mix isready for delivery to the web-forming device, because of the deleteriousaction of alkaline filler on the size precipitate and also on any excessalum which may be added to the mix. If such mix is run off on a papermachine the resulting paper will be substantially unsized or will have"only a relatively minor degree of sizing. By applying to a paper web somade a suitable sizing affecting agent, the destroyed or deterioratedsizing present in the web functions as potential sizing which is madeactive, or converted into effective sizing, by said closure of my PatentNo. 1,803,647, e. g. by mixing fibre with size and precipitating saidsize just prior to web formation, the paper will be well sized; but byapplying to a paper web so produced a suitable sizing affecting agent,the sizing of the sheet is improved.

(4) In my Patent No. 1,803,642, issued May 5, 1931, I disclose a methodfor the manufacture of sized paper filled with alkaline filler, byadding the filler to previously sized paper mix just prior to webformation. By applying a suitable sizing affecting agent to a paper webso produced, the sizing of the sheet is improved.

(5) In my copending application Serial No. 533,571, filed April 28,1931, I disclose a temporarily protected alkaline filler, and in myPatent No. 1,879,483,'issued September 27, 1932, I disclose an alkalinefiller with a pH value substantially stabilized by the use of an acidicma- I terial such as alum. The use of these fll 's in sized paper, whilehaving less deleterious effect on the sizing than untreated alkalinefiller, nevertheless is accompanied in some instances by some 1deterioration of the sizing effect of the paper, and

- when mixes containing such flllersare run off on the paper machine theapplication of a sizing af- 1' ecting agent to the paper web results inimproved sizing effect being obtained from suchmixes.

(6) In my Patent No. 1,819,441, issued August 18, 1931, I disclose thefact that an alkaline filler such as a carbonate when treated with anemulsion of material such as paraflin which is substantially unaffectedby alkaline filler, will form a complex, which may be considered as aprotected alkaline filler. When such a filler is employed in themanufacture of sized paper, in which if desired sizing agents inaddition to parafiin, such as rosin size and the like, may be used, asatisfactorily sized paper is produced, but I have found that in someinstances a certain deterioration in sizing eifect results and in suchcases by the application of a sizing affecting agent to the web, thesizing effect of the sizing in the sheet may be enhanced. This is eventrue in some cases where a restoring agent is additionally employed atthe dilute stage.

(7) It has been proposed to treat alkaline filler with an emulsion of afatty acid in order to obtain on the particles of the filler asuperficial coating of a reaction product of the particles and the saidfatty acid radicle, and then to employ this filer in the manufacture ofsized paper employing rosin size as the sizing agent. When this practicehas hitherto been attempted, it has been found that the paper madetherewith is not thoroughly amenable to steam drying which makes theprocess impractical for use from an industrial standpoint, as theordinary types of papers made on a commercial scale are for the mostpart dried completely on drying cylinders heated by steam, or, incertain grades of limited production such as in writing paper, at leastpartially so. However, by the employment of my process, this formerproposal, infeasible of application commercially in the form proposed,now becomes a possible commercial procedure as by the application of asizing affecting agent to a paper web containing said treated alkalinefiller and sizing and/or deteriorated or destroyed or the like sizing,the sizing is maintained or preserved and/or developed and a well sizedsheet results.

(8) As described in my Patent No. 1,803,643, in some instances, certainprecipitants, e. g. sodium bisulphate, may be used with sizing agents ina paper mix containing alkaline filler, which precipitants while theyconvert the sizing agent into an insoluble form, nevetheless convert itinto a form which may produce a lesser sizing effect than does alum; orin some cases certain precipitants produce substantially no sizingeffect at all. Such precipitants prevent to a substantial degree thephysical loss' of the soluble or emulsified sizing agent in the eflluentwaters of the papermaking process, but as stated above they may imparteither no, or only relatively poor, sizing effect to the resultantpaper, that is they produce undeveloped or underdeveloped sizing.Examples of precipitants other than sodium bisulphate which produce suchinferior effects are,

in certain instances, calcium compounds for ex- (9) In certain cases inalkaline filler fibrous 'mixes a non-acid compound of aluminum, suchassodium aluminate, may be employed in conjunction with size such asrosin size. Alum may be additionally employed either in the concentratedand/or dilute stage of the papermaking process. Such mixes may atcertain times and under some conditions, especially if no, or onlyinsufficient, alum be used, produce a sheet with substantially no sizingeffect or with inferior sizing effect. By the application of a sizingaffecting agent to paper webs made from such mixm, satisfactorily sizedpapers result.

' (10) In various of my prior patents (e. g.Nos. 1,803,645 and1,803,651), I disclose processes of using emulsions of substantiallywater insoluble sizing agents such as paraflin, wherein such emulsionsmay be associated with the fibre, for example by mutually precipitatingflbre associating agents. In such cases, the application of a sizingaffecting agent to the paper web. in certain instances, enhances thesizing eflect. Also, if there be a deficiency of fibre associating agentin the mix, or if such agents be deteriorated, or even completelylacking, fibrous webs formed from such mixes will have their sizingmaterially improved by the application of sizing affecting agent theretoin accordance with the present invention.

The sizing aflecting agent which I employ for the restoration,preservation, improvement or the like of the sizing in the paper webalready containing alkaline filler and either undeveloped,underdeveloped, destroyed or deteriorated sizing or sizing capable ofpreservation or enhancement,

or the like, may be either gaseous, liquid or solid. It is usually ofsuch a nature that, when caused to contact with a solution of rosinsize, it .will precipitate such size. Forinstance acidic material ingeneral may function, such for example as acetic acid or other organicor mineral acid as sulphuric or phosphoric acid, or acid salts such assodium bisulphate. The acids may conveniently be applied to the web inliquid form, preferably in aqueous solution, but it is also possible toapply at least certain of them such as formic, acetic, or hydrochloricacid in gaseous form; and also to apply acids or acid anhydrides whichoccur in gaseous form at temperatures which will not substantiallyinJure cellulose fibre. Thus, for example,carbon dioxide or sulphurdioxide may be employed although in such cases there should preferablybe water or aqueous vapor present in order to make them functionproperly. In addition to such acidic anhydrides, other gaseous materialsmay be used in certain instances such as aldehydes, for exampleformaldehyde, and as will be apparent, such may be used in solution aswell as in the gaseous phase.

Likewise, the agent may be applied to the web in solid form. For exampleany solid acid, preferably finely powdered, such asoxalic acid, or

the like may be employed. In this case also water should preferably bepresent in the web to effect the solution of the agent in order that itmay have the proper effect on the web. Among other agents which I mayemploy in addition to those mentioned are metallic compounds, preferablysoluble, and thus in the claims where I use the term metallic compound Imean that such compound shall be substantially water soluble such forexample as calcium compounds as calcium nitrate, or magnesium sulphateand the like, which may be non-acid or which may be acid, such asaluminum sulphate (ordinary alum) or other aluminum compound such asaluminum chloride, or stannous chloride, lead acetate and the like.

However in general, from the standpoint of economy and effectiveness, Iprefer to use alum as my sizing afiecting agent and because ofconvenience in handling it, I prefer to apply it to. the web in aqueoussolution.

The application, 1'. e. exposure, of the sizing afiecting agent ingaseous or vapor form to the web may take place when the web is eitherin the wet or in the dry condition, but preferably when it isin the wetcondition, and will ordinarily require a container, hood or the like inwhich the sizing afiecting agent may be exposed to the web. This maysuitably be provided by enclosing that part of the paper machine atwhich the exposure is to be made in' a suitable hood or enclosure or thelike, which.may. be at atmospheric pressure. superatmospheric pressure,or sub-atmospheric pressure such as in a vacuum of suitable degree, asbest meets the particular case; or such agent may be applied to the web,independently of the paper machine in a special applying device.

The application of a liquid to the web, andthis is my preferred method,may conveniently take place on the paper machine but here again as inthe case of the gaseous agent, the liquid may if desired be applied to'the web as a process independent of the paper machine. The abovestatement relative to place of application ofa liquid is equallypertinent to the application of a solid. sizing aflecting agent. i

'The application of the sizing affecting agent to the web may take placewhile the web is either in the wet or the substantially dry condition,but in my preferred practice ot'using a liquid agent such as' alumsolution,-I prefer to apply it to the already formed wet web after ithas left the webfo'rming device, as this fits in most conveniently withthe ordinary papermahng operation and does not usually require specialdrierssubsequent to the point of application of the agent, as might bethe case if the agent were applied to the dried or almost dry web. Itwill be understood, however, that where I speak of applying a sizingaffecting agent to the web, I mean to include in the definition of weband as within the scope of my invention not only the already formed wetor dry web, but also the web as .it exists in its formative or formingstate at any point on the web-forming device, between the point ofdelivery of the mix to the web forming device and the point of deliveryof the formed web from the web-forming device; and of course it will beunderstood that such application may take place to ether side of theweb. that is, either the top or the bottom or to both. While the web ison said web-forming device this application will of course include thecase where the agentmay be introduced not at the surface but within theforming web by suitable introducing devices.

In the application of the'sizing aifecting agent in solution to the web,anyknown form 0! device for applying liquids to a paper web may beemployed; for example, the web may be passed through a trough or vatcontaining the solution, or the solution may be transferred to the wehbybrushes, for example rotary brushes, or by'contact rolls, or by supplyboxes or rolls on the press rolls or other rolls, or by spraying or thelike. In the case of spraying the spray may be relatively coarse, or itmay be very fine so as to be in theform of a mist, if desired.

In certainca'ses the sizing affecting agent may be applied by means ofthe felt or felts normally contacting with the web on the paper machine,or even by means of small independent travelling 15 felt or felts, orbelts, contacting with the web. In such cases the agent may be appliedpreviously to the felt, or the like, or may be applied at the nip of thecontacting web and felt. However, the application by roll or rolls is assimple as any'and thoroughly practical, and hence is'a very convenientone to use. In order to obtain more complete penetration of the web bythe sizing affecting agent, the web may be led over a suction box, roll,or the like at or subsequent to the point where the sizing affectingagent is applied to the opposite side of the web, particularly in thecase where the sizing aflecting agent is applied only to one side of theweb, or to the two sides at spaced intervals. If desired a felt, wirebelt, or the like may be interposed between the suction device and theweb to carry and/or support the web. In general the method ofapplication in any given case is that which is best adapted for use atthe particular point at which the agent is to be applied and should bechosen with regard to the particular conditions to be met in anygiven'case, all of which will be apparent to one skilled in the art.

As the agent is preferably applied continuously to the web, suitablemeans for supplying it to the applying device, for example pumps, shouldbe employed, and the amounts applied should preferably vary regularlywith the paper machine speed and be adjustable to the various grades andweights of paper run.

In order more clearly to demonstrate the method of practicing myinvention, I give below an illustrative procedure which producessatisfactory results. A mix of fibre of any suitable kind is made forexample in a beater, and to this is added size, for example rosin size,size precipitant for example alum, and alkaline filler. The size may bepresent for example in an amount of 2 per cent., computed as dry rosinon the air dry weight of the fibre, and the alum in an amount of 3 percent. computed similarly, whereas the alkaline filler also similarlycomputed may be present in an amount of 20 per cent. After this mix hasbeen suitably treated and is ready for delivery to a web-forming device,if paper be made therefrom, it will be found that said paper issubstantially unsized, or at best only very slightly sized, although asexplained above, there is present a potential sizing agent in the formof the deteriorated or destroyed sizing. This potential sizing agent is,in certain cases at least, not in a soluble form, but in an insolubleform, and there is some evidence to indicate that where rosin size isused and calcium carbonate is the filler, that the sizing which mayoriginally be considered to consist of aluminum resinate has beenconverted into calcium resinate. However this may be, and it is to bedistinctly understood that this is merely a theory, and that the resultsof my invention are in no way dependent upon this or any other theory,the mix which would otherwise produce an unsized or poorly sized sheetis run off on a paper machine equipped to apply alum to the web. Thisequipment may suitably be arranged at the presses, preferably the thirdpress, or even better at the smooth rolls if the machine be equippedwith such rolls. At such points the web has lost most, if not all of thewater which it will lose by pressure,- and is in a reasonably absorbentcondition. Thus, if the machine be equipped with third press rolls whichmay be operated preferably without felts, two applying rolls contactingdirectly with the two third press rolls may be used to apply the alumsolution to the wet web. Of course, it will be understood that thecontact rolls are supplied with the alum solution by appropriate meanssuch as by immersion in supply boxes, troughs or the like, or by contactwith other rolls carrying the alum solution, or other suitable means.Optionally, and in certain cases this is my preferred method, the alummay be applied by an applying roll which contacts directly with the webitself, and as will be apparent, either in this case or in the case ofpress roll application, the alum may be applied either to one or bothsides, but the application to both sides of the web is the more generalprocedure. After the alum application, the paper may be dried in thecustomary manner if desired, and calendered or otherwise finishedaccording tothe type of paper being made. The result of the applicationof this alum is that the paper instead of being unsized when it comesoff the machine will now be found to be sized. It will be apparent thatthis is accomplished by extremely simple means which may comprise asstated merely an alum applying device adapted to be easily and simplyattached to an ordinary paper machine.

While I do not limit myself to the concentration of alum solution to beapplied, and it will be apparent that the concentration required will inany event be influenced by machine speed, type of paper manufactured,and other variables well known to one skilled in the art, nevertheless Ican state that a 15 per cent. solution has been found to be satisfactoryfor my purpose, and this can be the one tried in practice first and thenadjustment of the concentration may be made either one way or the otheraccording to conditions. However, in certain cases, for example ifsuction is to be applied to the sheet to improve the penetration of thesizing affecting agent, a much more dilute solution may be employed, for

example 1 per cent. or thereabouts. Likewise the amount of alum to beapplied is diflicult to state definitely owing to the variation inconditions, and type of paper made, but it may vary in certain casesfrom a fraction of a percent. on the total furnish up to severalpercent., and this quantity may be conveniently controlled by the agentapplying device in conjunction with the adjustment of the concentrationof the solution applied. I

As will be apparent my process may be employed in combination with otherprocedures disclosed in numerous of my prior patents and copendingapplications, including not only those mentioned herein previously, butothers not speciflcally referred to previously herein. For example,itmay be applied in conjunction with the process described in my copendingapplication first above mentioned. In such an instance deteriorated ordestroyed sizing or sizing capable of preservation or enhancement wouldalready be present in a paper web, for improvement of the sizing by thepresent invention; and in addition extra sizing might be added to theweb by the process described in said copending application byprecipitating size in the web itself. It will be apparent that thesizing affecting agent may be applied to one side of the web only. Alsoif desiredother sizing methods'may be applied to the other side of theweb; or the present and other procedures may be-applied to the sameside, or to both sides; the use of any or all of these precedures aswill be apparent depending upon the circumstances and the results to beobtained.

It will be apparent that the application of the sizing affecting agentto the web will contact such agent not only with the potential sizing ofthe web, but also with the alkaline filler contained therein. If theagent be one which does not substantially react with alkaline filler,this will merely result in the co-presence in the web of the alkalinefiller and such amount of the agent as does not react with the potentialsizing in the web. Of course, such amount of agent will in general beconcentrated more nearly at one or both surfaces of the web than at thecentral portion of the'web, according as the application has taken placeto one or both surfaces.

However if the sizing affecting agent be one which reacts with alkalinefiller such as an acidic reagent, it will be apparent that the agent mayto a certain extent react with the alkaline filler itself in the webeither before, simultaneously with, or subsequent to, reacting with thepotential sizing of the web. -As will-be apparentsuch action'will resultin a change in the chemical composition of the alkaline filler, at leaston the surface of the alkaline filler particles, the

reaction taking place more particularly with those particles of thealkaline filler which are near the, superficial part of the web, thisaction taking place either at one or both sides of the web according asthe application of the agent is made to one or both sides of the web;and in certain cases as will be apparent the'pH value of the compoundformed will be different from that of the alkaline filler itself, inmost cases less. For example, if acetic acid be used as the agent andcalcium carbonate as the filler, a certain amount of calcium acetate maybe produced. On the other hand with calcium carbonate, an acid or anacid salt be used of which the calcium salt is substantially insoluble,that corresponding salt will be formed; for example if phosphoric acidor an acid phosphate be the agent used, calcium phosphate will beformed; if sulphuric acid or acid sulphate such as alum be used, calciumsulphate will be formed, as well as aluminum hydroxide or other aluminumcompound where alum is used.

This formation is beneficial in certain cases as under ordinaryconditions a paper filled with alkaline filler is more or less alkalinein reaction which, with certain inks and under certain conditions suchfor example as in the lithographic process, may be detrimental. However,by converting the alkaline filler, or at least the surface of itsparticles, at or near the surface or surfaces of the paper web, into asubstantially neutral or even acidic compound, a paper is producedfilled with alkaline filler which in its surface reaction may be of adifferent pH than its central portion, for example the surface reactionmay be only mildly alkaline, i. e. less alkaline than the alkalinefilleremployed, or neutral, or even acidic. This is due to the production ofthe corresponding diiferentpH value, or less alkaline, neutral, or evenacidic compound of the'metallic radicle of the alkaline filler throughthe reaction of the sizing affecting agent with the alkaline filler inthe paper web, and in certain cases to residual substantially unactedupon portions of the agent remaining in the web.

It will be apparent that where I use the term potential sizing I use itto include sizing in a number of possible conditions; and where I use itin the claims I mean it to include, among others, one or more of thefollowing: (1) deteriorated sizing; (2) destroyed sizing; (3)undeveloped sizing; (4) underdeveloped sizing; (5)

sizLng substantially developed but capable of improvement; (6) sizingsubstantially effective or substantially undeteriorated but which wouldsuffer deterioration during the drying process were it not preventedfrom being so affected; (7) unprecipitable sizing; (8) sizing comprisingsizing agent, which of itself may be material substantially unaffectedby alkaline filler, and which may be made eifective as sizing byassociating it with the fibres of a mix by means of acidic material orthe like, and which may not function properly as a sizing because of thelack of associating agent or the deterioration thereof; (9) similar to(8) except that instead of an individual material as fibre associatingagent, a gathering precipitate for the sizing agent such as a smallamount of rosin size and alum is used, (which may of itselfimpart sizingbut which need not be present in an amount sufiicient of itself toimpart sizing), and which sizing agent -may not function properly as asizing because of It will be apparent, however, that I do not mean toinclude in the term potential sizing the case where there is added inthe mix or to the web a soluble or emulsified sizing agent precipitablebut theretofore un'precipitated, such case being covered by claims inimycopending application first above mentioned.

By the term alkaline filler" I mean substantially water insoluble fillerwhich when agitated in contact with freshly boiled distilled water, sayfor an hour, will impart a pH value to such water greater than 7.0, thatis, whichwill be on the alkaline side of the neutral point; 'Amongfillers in this group may be mentioned calcium carbonate, of which limemud from the causticizing process is one form; calcium carbonatemagnesium basic carbonate employed in the paper disclosed in my UnitedStates Patent No. 1,595,416, issued August 10, 1926; calcium carbonatemagnesium hydroxide disclosed in my -or other physically associatedmixtures of these with one or more other acid soluble materials of asubstantially water insoluble nature. By the term alkaline filler I alsointend to include fibrous material and/or other material. such as papercoating constituents or the like containing one or more compounds of thecharacter referred to, such as old papers or similar papers, broke", orthe like.

Where I use the term size or sizing agent herein I mean to include anysize suitable for sizing paper, such for example as rosin size of anyknown composition, saponifled fatty acids or waxes, emulsions ofsubstantially non-saponifiable materials as paraflin, and the like.

When I use the-word paper" herein, I use it in the broad sense toinclude products of manufacture of all types and of all weights andthicknesses, which contain as an essential constituent a considerableamount of prepared fibre and which are capable of being produced on aFourdrinier, cylinder, or other forming, felting, shaping or moldingmachine.

While I have described in detail various embodiments and examples of myinvention, it is to be understood that the details of procedure andequipment, the proportions of ingredients, and the arrangement of stepsmay be widely varied without departing from the spirit of my inventionor the scope of the subjoined claims.

I claim:

1. The method of manufacturing sized paper filled with alkaline fillercomprising mixing fibrous material, alkaline filler, size, and sizeprecipitant, forming a web therefrom, and applying sizing affectingagent to said web.

2. The method of manufacturing sized paper filled with alkaline filler,wherein material is added to the paper mix under conditions favoring theof the time of contact of the constituents of the mix, comprising mixingfibrous material, alkaline filler, size, and size precipitant, forming aweb therefrom, and applying sizing afiecting agent to said web.

3. The method of manufacturing sized paper filled with alkaline fillercomprising'providing a fibrous mix containing alkaline filler andpotential sizing, forming a web therefrom, and apply ing sizingafiecting agent, to said web.

4. The method of manufacturing sized paper.

filled with alkaline filler comprising providing a fibrous mixcontaining alkaline filler and potential sizing, forming a webtherefrom, and applying acidic material to said web.

5. The method of manufacturing sized paper filled with alkaline fillercomprising providing a fibrous mix containing alkaline filler andpotential sizing, forming a web therefrom, and applying metalliccompound to said web.

6. The method of manufacturing sized paper filled with alkaline fillercomprising providing a fibrous mix containing alkaline filler andpotential sizing, forming a web therefrom, and applying alum to saidweb.

7. That step in a method of manufacturing sized paper filled withalkaline filler comprising applying sizing affecting agent to a paperweb containing alkaline filler and potential sizing.

8. That step in a method of manufacturing sized paper filled withalkaline filler comprising applying acidic material to a paper webcontaining alkaline filler and potential sizing.

9. That step in a method of manufacturing sized paper filled withalkaline filler comprising applying metallic compound to a paper webcontaining alkaline filler 'and potential sizing.

10. That step in a method of manufacturing sized paper filled withalkaline filler comprising applying alum to a paper web containingalkaline fillerand potential sizing.

11. That step in a process of manufacturing sized paper filled withalkaline filler comprising substantially preservingthe sizing in a paperweb containing alkaline filler and sizing, by the application of asizing affecting agent to said paper web.

12. That step in a process of manufactin'ing sized paper filled withalkaline filler comprising substantially developing the sizing in apaper web containingalkaline filler and one of a group of materialscomprising sizing capable of improvement, deteriorated sizing, destroyedsizing, undeveloped sizing, and underdeveloped sizing, by theapplication of; a sizing affecting agent to said paper web.

l3. Sized paper filled with alkaline filler, at least one surface ofwhich paper is less alkaline than said alkaline filler.

14. Sized paper filled with alkaline filler, said paper being'lessalkaline at at least one of its surfaces than it is in its centralportion.

15. Sized paper filled with alkaline filler, at least one surface ofwhich paper is substantially non-alkaline.

l6. Sized paper filled with alkaline filler, at leastone surface 'ofwhich paper is acidic.

l7. Sized paper filled with alkaline filler having a conversion productformed in situ from alkaline filler, adjacent at least one of thesurfaces of said paper.

l8. Sized paper filled with alkaline filler, the particles of saidfiller near the surface of said paper having a coating thereoncomprisinga compound of a lower pH value than said alkaline filler, said'co'mpoundhaving a higher concentration adjacent at least one of the surfaces ofsaid paper than it has at the central portion of said 19. Sizedpaperfilled with alkaline filler, having a substantially non-alkalinecompound formed in situ from alkaline filler adjacent at least one ofthe surfaces of said paper.

. 20. Sized paper'filled with alkaline filler comprising calciumcarbonate at least part of which is superficially coated with a reactionproduct of a pH value different from said calcium carbonate, saidreaction product being formed in situ.

21. Sized paper filled with alkaline filler comprising calcium carbonateat least part of which is superficially coatedwith calcium sulphate.

22. Sized paper filled with alkaline filler, containing residualsubstantially unafiected sizing affecting agent adjacent at least one ofthe surfaces of said paper.

23. Sized paper filled with alkaline filler, the

sizing eflect therein decreasing substantially gradually from at leastone surface thereof toward the center of the web.

HAROLD ROBERT RAFI'ON.

